State Government
(1) Business in a State Legislature is transacted in the State's official language(s), or in Hindi, or in English - though the presiding officer may permit a member unable to adequately use those to address the House in their mother tongue. (2) Unless the state Legislature provides otherwise, this continues indefinitely (an original 15-year sunset on English usage - 25 or 40 years for certain specified states - was never actually allowed to take effect).
This mirrors Article 120 at the state level: State Assemblies conduct business in the state's own official language(s), Hindi, or English, with special permission available for members who struggle in all of these. As with Parliament, states exercised their power to keep English in permanent use rather than letting the original phase-out timeline take effect.
This is why a state Assembly debate might be conducted primarily in the state's own regional language (like Tamil, Telugu, or Marathi), with Hindi and English also permitted, rather than being restricted to just one language.